SDL 3.0
SDL_iostream.h File Reference
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Data Structures

struct  SDL_IOStreamInterface
 

Typedefs

typedef struct SDL_IOStream SDL_IOStream
 

Enumerations

enum  SDL_IOStatus {
  SDL_IO_STATUS_READY ,
  SDL_IO_STATUS_ERROR ,
  SDL_IO_STATUS_EOF ,
  SDL_IO_STATUS_NOT_READY ,
  SDL_IO_STATUS_READONLY ,
  SDL_IO_STATUS_WRITEONLY
}
 
enum  SDL_IOWhence {
  SDL_IO_SEEK_SET ,
  SDL_IO_SEEK_CUR ,
  SDL_IO_SEEK_END
}
 

Functions

 SDL_COMPILE_TIME_ASSERT (SDL_IOStreamInterface_SIZE,(sizeof(void *)==4 &&sizeof(SDL_IOStreamInterface)==28)||(sizeof(void *)==8 &&sizeof(SDL_IOStreamInterface)==56))
 
Read endian functions

Read an item of the specified endianness and return in native format.

bool SDL_ReadU8 (SDL_IOStream *src, Uint8 *value)
 
bool SDL_ReadS8 (SDL_IOStream *src, Sint8 *value)
 
bool SDL_ReadU16LE (SDL_IOStream *src, Uint16 *value)
 
bool SDL_ReadS16LE (SDL_IOStream *src, Sint16 *value)
 
bool SDL_ReadU16BE (SDL_IOStream *src, Uint16 *value)
 
bool SDL_ReadS16BE (SDL_IOStream *src, Sint16 *value)
 
bool SDL_ReadU32LE (SDL_IOStream *src, Uint32 *value)
 
bool SDL_ReadS32LE (SDL_IOStream *src, Sint32 *value)
 
bool SDL_ReadU32BE (SDL_IOStream *src, Uint32 *value)
 
bool SDL_ReadS32BE (SDL_IOStream *src, Sint32 *value)
 
bool SDL_ReadU64LE (SDL_IOStream *src, Uint64 *value)
 
bool SDL_ReadS64LE (SDL_IOStream *src, Sint64 *value)
 
bool SDL_ReadU64BE (SDL_IOStream *src, Uint64 *value)
 
bool SDL_ReadS64BE (SDL_IOStream *src, Sint64 *value)
 
Write endian functions

Write an item of native format to the specified endianness.

bool SDL_WriteU8 (SDL_IOStream *dst, Uint8 value)
 
bool SDL_WriteS8 (SDL_IOStream *dst, Sint8 value)
 
bool SDL_WriteU16LE (SDL_IOStream *dst, Uint16 value)
 
bool SDL_WriteS16LE (SDL_IOStream *dst, Sint16 value)
 
bool SDL_WriteU16BE (SDL_IOStream *dst, Uint16 value)
 
bool SDL_WriteS16BE (SDL_IOStream *dst, Sint16 value)
 
bool SDL_WriteU32LE (SDL_IOStream *dst, Uint32 value)
 
bool SDL_WriteS32LE (SDL_IOStream *dst, Sint32 value)
 
bool SDL_WriteU32BE (SDL_IOStream *dst, Uint32 value)
 
bool SDL_WriteS32BE (SDL_IOStream *dst, Sint32 value)
 
bool SDL_WriteU64LE (SDL_IOStream *dst, Uint64 value)
 
bool SDL_WriteS64LE (SDL_IOStream *dst, Sint64 value)
 
bool SDL_WriteU64BE (SDL_IOStream *dst, Uint64 value)
 
bool SDL_WriteS64BE (SDL_IOStream *dst, Sint64 value)
 

IOFrom functions

Functions to create SDL_IOStream structures from various data streams.

#define SDL_PROP_IOSTREAM_WINDOWS_HANDLE_POINTER   "SDL.iostream.windows.handle"
 
#define SDL_PROP_IOSTREAM_STDIO_FILE_POINTER   "SDL.iostream.stdio.file"
 
#define SDL_PROP_IOSTREAM_FILE_DESCRIPTOR_NUMBER   "SDL.iostream.file_descriptor"
 
#define SDL_PROP_IOSTREAM_ANDROID_AASSET_POINTER   "SDL.iostream.android.aasset"
 
#define SDL_PROP_IOSTREAM_MEMORY_POINTER   "SDL.iostream.memory.base"
 
#define SDL_PROP_IOSTREAM_MEMORY_SIZE_NUMBER   "SDL.iostream.memory.size"
 
#define SDL_PROP_IOSTREAM_DYNAMIC_MEMORY_POINTER   "SDL.iostream.dynamic.memory"
 
#define SDL_PROP_IOSTREAM_DYNAMIC_CHUNKSIZE_NUMBER   "SDL.iostream.dynamic.chunksize"
 
SDL_IOStreamSDL_IOFromFile (const char *file, const char *mode)
 
SDL_IOStreamSDL_IOFromMem (void *mem, size_t size)
 
SDL_IOStreamSDL_IOFromConstMem (const void *mem, size_t size)
 
SDL_IOStreamSDL_IOFromDynamicMem (void)
 
SDL_IOStreamSDL_OpenIO (const SDL_IOStreamInterface *iface, void *userdata)
 
bool SDL_CloseIO (SDL_IOStream *context)
 
SDL_PropertiesID SDL_GetIOProperties (SDL_IOStream *context)
 
SDL_IOStatus SDL_GetIOStatus (SDL_IOStream *context)
 
Sint64 SDL_GetIOSize (SDL_IOStream *context)
 
Sint64 SDL_SeekIO (SDL_IOStream *context, Sint64 offset, SDL_IOWhence whence)
 
Sint64 SDL_TellIO (SDL_IOStream *context)
 
size_t SDL_ReadIO (SDL_IOStream *context, void *ptr, size_t size)
 
size_t SDL_WriteIO (SDL_IOStream *context, const void *ptr, size_t size)
 
size_t SDL_IOprintf (SDL_IOStream *context, SDL_PRINTF_FORMAT_STRING const char *fmt,...) SDL_PRINTF_VARARG_FUNC(2)
 
size_t SDL_IOvprintf (SDL_IOStream *context, SDL_PRINTF_FORMAT_STRING const char *fmt, va_list ap) SDL_PRINTF_VARARG_FUNCV(2)
 
bool SDL_FlushIO (SDL_IOStream *context)
 
void * SDL_LoadFile_IO (SDL_IOStream *src, size_t *datasize, bool closeio)
 
void * SDL_LoadFile (const char *file, size_t *datasize)
 
bool SDL_SaveFile_IO (SDL_IOStream *src, const void *data, size_t datasize, bool closeio)
 
bool SDL_SaveFile (const char *file, const void *data, size_t datasize)
 

Macro Definition Documentation

◆ SDL_PROP_IOSTREAM_ANDROID_AASSET_POINTER

#define SDL_PROP_IOSTREAM_ANDROID_AASSET_POINTER   "SDL.iostream.android.aasset"

Definition at line 279 of file SDL_iostream.h.

◆ SDL_PROP_IOSTREAM_DYNAMIC_CHUNKSIZE_NUMBER

#define SDL_PROP_IOSTREAM_DYNAMIC_CHUNKSIZE_NUMBER   "SDL.iostream.dynamic.chunksize"

Definition at line 397 of file SDL_iostream.h.

◆ SDL_PROP_IOSTREAM_DYNAMIC_MEMORY_POINTER

#define SDL_PROP_IOSTREAM_DYNAMIC_MEMORY_POINTER   "SDL.iostream.dynamic.memory"

Definition at line 396 of file SDL_iostream.h.

◆ SDL_PROP_IOSTREAM_FILE_DESCRIPTOR_NUMBER

#define SDL_PROP_IOSTREAM_FILE_DESCRIPTOR_NUMBER   "SDL.iostream.file_descriptor"

Definition at line 278 of file SDL_iostream.h.

◆ SDL_PROP_IOSTREAM_MEMORY_POINTER

#define SDL_PROP_IOSTREAM_MEMORY_POINTER   "SDL.iostream.memory.base"

Definition at line 322 of file SDL_iostream.h.

◆ SDL_PROP_IOSTREAM_MEMORY_SIZE_NUMBER

#define SDL_PROP_IOSTREAM_MEMORY_SIZE_NUMBER   "SDL.iostream.memory.size"

Definition at line 323 of file SDL_iostream.h.

◆ SDL_PROP_IOSTREAM_STDIO_FILE_POINTER

#define SDL_PROP_IOSTREAM_STDIO_FILE_POINTER   "SDL.iostream.stdio.file"

Definition at line 277 of file SDL_iostream.h.

◆ SDL_PROP_IOSTREAM_WINDOWS_HANDLE_POINTER

#define SDL_PROP_IOSTREAM_WINDOWS_HANDLE_POINTER   "SDL.iostream.windows.handle"

Definition at line 276 of file SDL_iostream.h.

Typedef Documentation

◆ SDL_IOStream

typedef struct SDL_IOStream SDL_IOStream

The read/write operation structure.

This operates as an opaque handle. There are several APIs to create various types of I/O streams, or an app can supply an SDL_IOStreamInterface to SDL_OpenIO() to provide their own stream implementation behind this struct's abstract interface.

Since
This struct is available since SDL 3.2.0.

Definition at line 182 of file SDL_iostream.h.

Enumeration Type Documentation

◆ SDL_IOStatus

CategoryIOStream

SDL provides an abstract interface for reading and writing data streams. It offers implementations for files, memory, etc, and the app can provide their own implementations, too.

SDL_IOStream is not related to the standard C++ iostream class, other than both are abstract interfaces to read/write data. SDL_IOStream status, set by a read or write operation.

Since
This enum is available since SDL 3.2.0.
Enumerator
SDL_IO_STATUS_READY 

Everything is ready (no errors and not EOF).

SDL_IO_STATUS_ERROR 

Read or write I/O error

SDL_IO_STATUS_EOF 

End of file

SDL_IO_STATUS_NOT_READY 

Non blocking I/O, not ready

SDL_IO_STATUS_READONLY 

Tried to write a read-only buffer

SDL_IO_STATUS_WRITEONLY 

Tried to read a write-only buffer

Definition at line 53 of file SDL_iostream.h.

54{
55 SDL_IO_STATUS_READY, /**< Everything is ready (no errors and not EOF). */
56 SDL_IO_STATUS_ERROR, /**< Read or write I/O error */
57 SDL_IO_STATUS_EOF, /**< End of file */
58 SDL_IO_STATUS_NOT_READY, /**< Non blocking I/O, not ready */
59 SDL_IO_STATUS_READONLY, /**< Tried to write a read-only buffer */
60 SDL_IO_STATUS_WRITEONLY /**< Tried to read a write-only buffer */
SDL_IOStatus
@ SDL_IO_STATUS_ERROR
@ SDL_IO_STATUS_EOF
@ SDL_IO_STATUS_NOT_READY
@ SDL_IO_STATUS_READY
@ SDL_IO_STATUS_WRITEONLY
@ SDL_IO_STATUS_READONLY

◆ SDL_IOWhence

Possible whence values for SDL_IOStream seeking.

These map to the same "whence" concept that fseek or lseek use in the standard C runtime.

Since
This enum is available since SDL 3.2.0.
Enumerator
SDL_IO_SEEK_SET 

Seek from the beginning of data

SDL_IO_SEEK_CUR 

Seek relative to current read point

SDL_IO_SEEK_END 

Seek relative to the end of data

Definition at line 71 of file SDL_iostream.h.

72{
73 SDL_IO_SEEK_SET, /**< Seek from the beginning of data */
74 SDL_IO_SEEK_CUR, /**< Seek relative to current read point */
75 SDL_IO_SEEK_END /**< Seek relative to the end of data */
SDL_IOWhence
@ SDL_IO_SEEK_CUR
@ SDL_IO_SEEK_SET
@ SDL_IO_SEEK_END

Function Documentation

◆ SDL_CloseIO()

bool SDL_CloseIO ( SDL_IOStream context)
extern

Close and free an allocated SDL_IOStream structure.

SDL_CloseIO() closes and cleans up the SDL_IOStream stream. It releases any resources used by the stream and frees the SDL_IOStream itself. This returns true on success, or false if the stream failed to flush to its output (e.g. to disk).

Note that if this fails to flush the stream for any reason, this function reports an error, but the SDL_IOStream is still invalid once this function returns.

This call flushes any buffered writes to the operating system, but there are no guarantees that those writes have gone to physical media; they might be in the OS's file cache, waiting to go to disk later. If it's absolutely crucial that writes go to disk immediately, so they are definitely stored even if the power fails before the file cache would have caught up, one should call SDL_FlushIO() before closing. Note that flushing takes time and makes the system and your app operate less efficiently, so do so sparingly.

Parameters
contextSDL_IOStream structure to close.
Returns
true on success or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_OpenIO

◆ SDL_COMPILE_TIME_ASSERT()

SDL_COMPILE_TIME_ASSERT ( SDL_IOStreamInterface_SIZE  ,
(sizeof(void *)==4 &&sizeof(SDL_IOStreamInterface)==28)||(sizeof(void *)==8 &&sizeof(SDL_IOStreamInterface)==56)   
)

◆ SDL_FlushIO()

bool SDL_FlushIO ( SDL_IOStream context)
extern

Flush any buffered data in the stream.

This function makes sure that any buffered data is written to the stream. Normally this isn't necessary but if the stream is a pipe or socket it guarantees that any pending data is sent.

Parameters
contextSDL_IOStream structure to flush.
Returns
true on success or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_OpenIO
SDL_WriteIO

◆ SDL_GetIOProperties()

SDL_PropertiesID SDL_GetIOProperties ( SDL_IOStream context)
extern

Get the properties associated with an SDL_IOStream.

Parameters
contexta pointer to an SDL_IOStream structure.
Returns
a valid property ID on success or 0 on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_GetIOSize()

Sint64 SDL_GetIOSize ( SDL_IOStream context)
extern

Use this function to get the size of the data stream in an SDL_IOStream.

Parameters
contextthe SDL_IOStream to get the size of the data stream from.
Returns
the size of the data stream in the SDL_IOStream on success or a negative error code on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_GetIOStatus()

SDL_IOStatus SDL_GetIOStatus ( SDL_IOStream context)
extern

Query the stream status of an SDL_IOStream.

This information can be useful to decide if a short read or write was due to an error, an EOF, or a non-blocking operation that isn't yet ready to complete.

An SDL_IOStream's status is only expected to change after a SDL_ReadIO or SDL_WriteIO call; don't expect it to change if you just call this query function in a tight loop.

Parameters
contextthe SDL_IOStream to query.
Returns
an SDL_IOStatus enum with the current state.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_IOFromConstMem()

SDL_IOStream * SDL_IOFromConstMem ( const void *  mem,
size_t  size 
)
extern

Use this function to prepare a read-only memory buffer for use with SDL_IOStream.

This function sets up an SDL_IOStream struct based on a memory area of a certain size. It assumes the memory area is not writable.

Attempting to write to this SDL_IOStream stream will report an error without writing to the memory buffer.

This memory buffer is not copied by the SDL_IOStream; the pointer you provide must remain valid until you close the stream. Closing the stream will not free the original buffer.

If you need to write to a memory buffer, you should use SDL_IOFromMem() with a writable buffer of memory instead.

The following properties will be set at creation time by SDL:

  • SDL_PROP_IOSTREAM_MEMORY_POINTER: this will be the mem parameter that was passed to this function.
  • SDL_PROP_IOSTREAM_MEMORY_SIZE_NUMBER: this will be the size parameter that was passed to this function.
Parameters
mema pointer to a read-only buffer to feed an SDL_IOStream stream.
sizethe buffer size, in bytes.
Returns
a pointer to a new SDL_IOStream structure or NULL on failure; call SDL_GetError() for more information.

\threadsafety It is safe to call this function from any thread.

Since
This function is available since SDL 3.2.0.
See also
SDL_IOFromMem
SDL_CloseIO
SDL_ReadIO
SDL_SeekIO
SDL_TellIO

◆ SDL_IOFromDynamicMem()

SDL_IOStream * SDL_IOFromDynamicMem ( void  )
extern

Use this function to create an SDL_IOStream that is backed by dynamically allocated memory.

This supports the following properties to provide access to the memory and control over allocations:

  • SDL_PROP_IOSTREAM_DYNAMIC_MEMORY_POINTER: a pointer to the internal memory of the stream. This can be set to NULL to transfer ownership of the memory to the application, which should free the memory with SDL_free(). If this is done, the next operation on the stream must be SDL_CloseIO().
  • SDL_PROP_IOSTREAM_DYNAMIC_CHUNKSIZE_NUMBER: memory will be allocated in multiples of this size, defaulting to 1024.
Returns
a pointer to a new SDL_IOStream structure or NULL on failure; call SDL_GetError() for more information.

\threadsafety It is safe to call this function from any thread.

Since
This function is available since SDL 3.2.0.
See also
SDL_CloseIO
SDL_ReadIO
SDL_SeekIO
SDL_TellIO
SDL_WriteIO

◆ SDL_IOFromFile()

SDL_IOStream * SDL_IOFromFile ( const char *  file,
const char *  mode 
)
extern

Use this function to create a new SDL_IOStream structure for reading from and/or writing to a named file.

The mode string is treated roughly the same as in a call to the C library's fopen(), even if SDL doesn't happen to use fopen() behind the scenes.

Available mode strings:

  • "r": Open a file for reading. The file must exist.
  • "w": Create an empty file for writing. If a file with the same name already exists its content is erased and the file is treated as a new empty file.
  • "a": Append to a file. Writing operations append data at the end of the file. The file is created if it does not exist.
  • "r+": Open a file for update both reading and writing. The file must exist.
  • "w+": Create an empty file for both reading and writing. If a file with the same name already exists its content is erased and the file is treated as a new empty file.
  • "a+": Open a file for reading and appending. All writing operations are performed at the end of the file, protecting the previous content to be overwritten. You can reposition (fseek, rewind) the internal pointer to anywhere in the file for reading, but writing operations will move it back to the end of file. The file is created if it does not exist.

NOTE: In order to open a file as a binary file, a "b" character has to be included in the mode string. This additional "b" character can either be appended at the end of the string (thus making the following compound modes: "rb", "wb", "ab", "r+b", "w+b", "a+b") or be inserted between the letter and the "+" sign for the mixed modes ("rb+", "wb+", "ab+"). Additional characters may follow the sequence, although they should have no effect. For example, "t" is sometimes appended to make explicit the file is a text file.

This function supports Unicode filenames, but they must be encoded in UTF-8 format, regardless of the underlying operating system.

In Android, SDL_IOFromFile() can be used to open content:// URIs. As a fallback, SDL_IOFromFile() will transparently open a matching filename in the app's assets.

Closing the SDL_IOStream will close SDL's internal file handle.

The following properties may be set at creation time by SDL:

  • SDL_PROP_IOSTREAM_WINDOWS_HANDLE_POINTER: a pointer, that can be cast to a win32 HANDLE, that this SDL_IOStream is using to access the filesystem. If the program isn't running on Windows, or SDL used some other method to access the filesystem, this property will not be set.
  • SDL_PROP_IOSTREAM_STDIO_FILE_POINTER: a pointer, that can be cast to a stdio FILE *, that this SDL_IOStream is using to access the filesystem. If SDL used some other method to access the filesystem, this property will not be set. PLEASE NOTE that if SDL is using a different C runtime than your app, trying to use this pointer will almost certainly result in a crash! This is mostly a problem on Windows; make sure you build SDL and your app with the same compiler and settings to avoid it.
  • SDL_PROP_IOSTREAM_FILE_DESCRIPTOR_NUMBER: a file descriptor that this SDL_IOStream is using to access the filesystem.
  • SDL_PROP_IOSTREAM_ANDROID_AASSET_POINTER: a pointer, that can be cast to an Android NDK AAsset *, that this SDL_IOStream is using to access the filesystem. If SDL used some other method to access the filesystem, this property will not be set.
Parameters
filea UTF-8 string representing the filename to open.
modean ASCII string representing the mode to be used for opening the file.
Returns
a pointer to the SDL_IOStream structure that is created or NULL on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_CloseIO
SDL_FlushIO
SDL_ReadIO
SDL_SeekIO
SDL_TellIO
SDL_WriteIO

◆ SDL_IOFromMem()

SDL_IOStream * SDL_IOFromMem ( void *  mem,
size_t  size 
)
extern

Use this function to prepare a read-write memory buffer for use with SDL_IOStream.

This function sets up an SDL_IOStream struct based on a memory area of a certain size, for both read and write access.

This memory buffer is not copied by the SDL_IOStream; the pointer you provide must remain valid until you close the stream. Closing the stream will not free the original buffer.

If you need to make sure the SDL_IOStream never writes to the memory buffer, you should use SDL_IOFromConstMem() with a read-only buffer of memory instead.

The following properties will be set at creation time by SDL:

  • SDL_PROP_IOSTREAM_MEMORY_POINTER: this will be the mem parameter that was passed to this function.
  • SDL_PROP_IOSTREAM_MEMORY_SIZE_NUMBER: this will be the size parameter that was passed to this function.
Parameters
mema pointer to a buffer to feed an SDL_IOStream stream.
sizethe buffer size, in bytes.
Returns
a pointer to a new SDL_IOStream structure or NULL on failure; call SDL_GetError() for more information.

\threadsafety It is safe to call this function from any thread.

Since
This function is available since SDL 3.2.0.
See also
SDL_IOFromConstMem
SDL_CloseIO
SDL_FlushIO
SDL_ReadIO
SDL_SeekIO
SDL_TellIO
SDL_WriteIO

◆ SDL_IOprintf()

size_t SDL_IOprintf ( SDL_IOStream context,
SDL_PRINTF_FORMAT_STRING const char *  fmt,
  ... 
)
extern

Print to an SDL_IOStream data stream.

This function does formatted printing to the stream.

Parameters
contexta pointer to an SDL_IOStream structure.
fmta printf() style format string.
...additional parameters matching % tokens in the fmt string, if any.
Returns
the number of bytes written or 0 on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_IOvprintf
SDL_WriteIO

◆ SDL_IOvprintf()

size_t SDL_IOvprintf ( SDL_IOStream context,
SDL_PRINTF_FORMAT_STRING const char *  fmt,
va_list  ap 
)
extern

Print to an SDL_IOStream data stream.

This function does formatted printing to the stream.

Parameters
contexta pointer to an SDL_IOStream structure.
fmta printf() style format string.
apa variable argument list.
Returns
the number of bytes written or 0 on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_IOprintf
SDL_WriteIO

◆ SDL_LoadFile()

void * SDL_LoadFile ( const char *  file,
size_t *  datasize 
)
extern

Load all the data from a file path.

The data is allocated with a zero byte at the end (null terminated) for convenience. This extra byte is not included in the value reported via datasize.

The data should be freed with SDL_free().

Parameters
filethe path to read all available data from.
datasizeif not NULL, will store the number of bytes read.
Returns
the data or NULL on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_LoadFile_IO
SDL_SaveFile

◆ SDL_LoadFile_IO()

void * SDL_LoadFile_IO ( SDL_IOStream src,
size_t *  datasize,
bool  closeio 
)
extern

Load all the data from an SDL data stream.

The data is allocated with a zero byte at the end (null terminated) for convenience. This extra byte is not included in the value reported via datasize.

The data should be freed with SDL_free().

Parameters
srcthe SDL_IOStream to read all available data from.
datasizea pointer filled in with the number of bytes read, may be NULL.
closeioif true, calls SDL_CloseIO() on src before returning, even in the case of an error.
Returns
the data or NULL on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_LoadFile
SDL_SaveFile_IO

◆ SDL_OpenIO()

SDL_IOStream * SDL_OpenIO ( const SDL_IOStreamInterface iface,
void *  userdata 
)
extern

Create a custom SDL_IOStream.

Applications do not need to use this function unless they are providing their own SDL_IOStream implementation. If you just need an SDL_IOStream to read/write a common data source, you should use the built-in implementations in SDL, like SDL_IOFromFile() or SDL_IOFromMem(), etc.

This function makes a copy of iface and the caller does not need to keep it around after this call.

Parameters
ifacethe interface that implements this SDL_IOStream, initialized using SDL_INIT_INTERFACE().
userdatathe pointer that will be passed to the interface functions.
Returns
a pointer to the allocated memory on success or NULL on failure; call SDL_GetError() for more information.

\threadsafety It is safe to call this function from any thread.

Since
This function is available since SDL 3.2.0.
See also
SDL_CloseIO
SDL_INIT_INTERFACE
SDL_IOFromConstMem
SDL_IOFromFile
SDL_IOFromMem

◆ SDL_ReadIO()

size_t SDL_ReadIO ( SDL_IOStream context,
void *  ptr,
size_t  size 
)
extern

Read from a data source.

This function reads up size bytes from the data source to the area pointed at by ptr. This function may read less bytes than requested.

This function will return zero when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If zero is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
contexta pointer to an SDL_IOStream structure.
ptra pointer to a buffer to read data into.
sizethe number of bytes to read from the data source.
Returns
the number of bytes read, or 0 on end of file or other failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_WriteIO
SDL_GetIOStatus

◆ SDL_ReadS16BE()

bool SDL_ReadS16BE ( SDL_IOStream src,
Sint16 value 
)
extern

Use this function to read 16 bits of big-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadS16LE()

bool SDL_ReadS16LE ( SDL_IOStream src,
Sint16 value 
)
extern

Use this function to read 16 bits of little-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadS32BE()

bool SDL_ReadS32BE ( SDL_IOStream src,
Sint32 value 
)
extern

Use this function to read 32 bits of big-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadS32LE()

bool SDL_ReadS32LE ( SDL_IOStream src,
Sint32 value 
)
extern

Use this function to read 32 bits of little-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadS64BE()

bool SDL_ReadS64BE ( SDL_IOStream src,
Sint64 value 
)
extern

Use this function to read 64 bits of big-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadS64LE()

bool SDL_ReadS64LE ( SDL_IOStream src,
Sint64 value 
)
extern

Use this function to read 64 bits of little-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadS8()

bool SDL_ReadS8 ( SDL_IOStream src,
Sint8 value 
)
extern

Use this function to read a signed byte from an SDL_IOStream.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe SDL_IOStream to read from.
valuea pointer filled in with the data read.
Returns
true on success or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadU16BE()

bool SDL_ReadU16BE ( SDL_IOStream src,
Uint16 value 
)
extern

Use this function to read 16 bits of big-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadU16LE()

bool SDL_ReadU16LE ( SDL_IOStream src,
Uint16 value 
)
extern

Use this function to read 16 bits of little-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadU32BE()

bool SDL_ReadU32BE ( SDL_IOStream src,
Uint32 value 
)
extern

Use this function to read 32 bits of big-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadU32LE()

bool SDL_ReadU32LE ( SDL_IOStream src,
Uint32 value 
)
extern

Use this function to read 32 bits of little-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadU64BE()

bool SDL_ReadU64BE ( SDL_IOStream src,
Uint64 value 
)
extern

Use this function to read 64 bits of big-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadU64LE()

bool SDL_ReadU64LE ( SDL_IOStream src,
Uint64 value 
)
extern

Use this function to read 64 bits of little-endian data from an SDL_IOStream and return in native format.

SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe stream from which to read data.
valuea pointer filled in with the data read.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_ReadU8()

bool SDL_ReadU8 ( SDL_IOStream src,
Uint8 value 
)
extern

Use this function to read a byte from an SDL_IOStream.

This function will return false when the data stream is completely read, and SDL_GetIOStatus() will return SDL_IO_STATUS_EOF. If false is returned and the stream is not at EOF, SDL_GetIOStatus() will return a different error value and SDL_GetError() will offer a human-readable message.

Parameters
srcthe SDL_IOStream to read from.
valuea pointer filled in with the data read.
Returns
true on success or false on failure or EOF; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_SaveFile()

bool SDL_SaveFile ( const char *  file,
const void *  data,
size_t  datasize 
)
extern

Save all the data into a file path.

Parameters
filethe path to write all available data into.
datathe data to be written. If datasize is 0, may be NULL or a invalid pointer.
datasizethe number of bytes to be written.
Returns
true on success or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_SaveFile_IO
SDL_LoadFile

◆ SDL_SaveFile_IO()

bool SDL_SaveFile_IO ( SDL_IOStream src,
const void *  data,
size_t  datasize,
bool  closeio 
)
extern

Save all the data into an SDL data stream.

Parameters
srcthe SDL_IOStream to write all data to.
datathe data to be written. If datasize is 0, may be NULL or a invalid pointer.
datasizethe number of bytes to be written.
closeioif true, calls SDL_CloseIO() on src before returning, even in the case of an error.
Returns
true on success or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_SaveFile
SDL_LoadFile_IO

◆ SDL_SeekIO()

Sint64 SDL_SeekIO ( SDL_IOStream context,
Sint64  offset,
SDL_IOWhence  whence 
)
extern

Seek within an SDL_IOStream data stream.

This function seeks to byte offset, relative to whence.

whence may be any of the following values:

  • SDL_IO_SEEK_SET: seek from the beginning of data
  • SDL_IO_SEEK_CUR: seek relative to current read point
  • SDL_IO_SEEK_END: seek relative to the end of data

If this stream can not seek, it will return -1.

Parameters
contexta pointer to an SDL_IOStream structure.
offsetan offset in bytes, relative to whence location; can be negative.
whenceany of SDL_IO_SEEK_SET, SDL_IO_SEEK_CUR, SDL_IO_SEEK_END.
Returns
the final offset in the data stream after the seek or -1 on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_TellIO

◆ SDL_TellIO()

Sint64 SDL_TellIO ( SDL_IOStream context)
extern

Determine the current read/write offset in an SDL_IOStream data stream.

SDL_TellIO is actually a wrapper function that calls the SDL_IOStream's seek method, with an offset of 0 bytes from SDL_IO_SEEK_CUR, to simplify application development.

Parameters
contextan SDL_IOStream data stream object from which to get the current offset.
Returns
the current offset in the stream, or -1 if the information can not be determined.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_SeekIO

◆ SDL_WriteIO()

size_t SDL_WriteIO ( SDL_IOStream context,
const void *  ptr,
size_t  size 
)
extern

Write to an SDL_IOStream data stream.

This function writes exactly size bytes from the area pointed at by ptr to the stream. If this fails for any reason, it'll return less than size to demonstrate how far the write progressed. On success, it returns size.

On error, this function still attempts to write as much as possible, so it might return a positive value less than the requested write size.

The caller can use SDL_GetIOStatus() to determine if the problem is recoverable, such as a non-blocking write that can simply be retried later, or a fatal error.

Parameters
contexta pointer to an SDL_IOStream structure.
ptra pointer to a buffer containing data to write.
sizethe number of bytes to write.
Returns
the number of bytes written, which will be less than size on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.
See also
SDL_IOprintf
SDL_ReadIO
SDL_SeekIO
SDL_FlushIO
SDL_GetIOStatus

◆ SDL_WriteS16BE()

bool SDL_WriteS16BE ( SDL_IOStream dst,
Sint16  value 
)
extern

Use this function to write 16 bits in native format to an SDL_IOStream as big-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in big-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteS16LE()

bool SDL_WriteS16LE ( SDL_IOStream dst,
Sint16  value 
)
extern

Use this function to write 16 bits in native format to an SDL_IOStream as little-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in little-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteS32BE()

bool SDL_WriteS32BE ( SDL_IOStream dst,
Sint32  value 
)
extern

Use this function to write 32 bits in native format to an SDL_IOStream as big-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in big-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteS32LE()

bool SDL_WriteS32LE ( SDL_IOStream dst,
Sint32  value 
)
extern

Use this function to write 32 bits in native format to an SDL_IOStream as little-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in little-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteS64BE()

bool SDL_WriteS64BE ( SDL_IOStream dst,
Sint64  value 
)
extern

Use this function to write 64 bits in native format to an SDL_IOStream as big-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in big-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteS64LE()

bool SDL_WriteS64LE ( SDL_IOStream dst,
Sint64  value 
)
extern

Use this function to write 64 bits in native format to an SDL_IOStream as little-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in little-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteS8()

bool SDL_WriteS8 ( SDL_IOStream dst,
Sint8  value 
)
extern

Use this function to write a signed byte to an SDL_IOStream.

Parameters
dstthe SDL_IOStream to write to.
valuethe byte value to write.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteU16BE()

bool SDL_WriteU16BE ( SDL_IOStream dst,
Uint16  value 
)
extern

Use this function to write 16 bits in native format to an SDL_IOStream as big-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in big-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteU16LE()

bool SDL_WriteU16LE ( SDL_IOStream dst,
Uint16  value 
)
extern

Use this function to write 16 bits in native format to an SDL_IOStream as little-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in little-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteU32BE()

bool SDL_WriteU32BE ( SDL_IOStream dst,
Uint32  value 
)
extern

Use this function to write 32 bits in native format to an SDL_IOStream as big-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in big-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteU32LE()

bool SDL_WriteU32LE ( SDL_IOStream dst,
Uint32  value 
)
extern

Use this function to write 32 bits in native format to an SDL_IOStream as little-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in little-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteU64BE()

bool SDL_WriteU64BE ( SDL_IOStream dst,
Uint64  value 
)
extern

Use this function to write 64 bits in native format to an SDL_IOStream as big-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in big-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteU64LE()

bool SDL_WriteU64LE ( SDL_IOStream dst,
Uint64  value 
)
extern

Use this function to write 64 bits in native format to an SDL_IOStream as little-endian data.

SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in little-endian format.

Parameters
dstthe stream to which data will be written.
valuethe data to be written, in native format.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.

◆ SDL_WriteU8()

bool SDL_WriteU8 ( SDL_IOStream dst,
Uint8  value 
)
extern

Use this function to write a byte to an SDL_IOStream.

Parameters
dstthe SDL_IOStream to write to.
valuethe byte value to write.
Returns
true on successful write or false on failure; call SDL_GetError() for more information.

\threadsafety This function is not thread safe.

Since
This function is available since SDL 3.2.0.