png_set_read_fn
Name
png_set_read_fn -- set user-defined function for reading a PNG stream
Synopsis
void
png_set_read_fn
(png_structp
png_ptr, png_voidp
io_ptr, png_rw_ptr
read_data_fn);
Description
png_set_read_fn() sets the read_data_fn as the input function for reading PNG
files instead of using standard C I/O stream functions.
png_ptr - pointer to input data structure png_struct
io_ptr - pointer to user-defined structure containing information about the
input functions. This value may be NULL.
read_data_fn - pointer to new input function that shall take the following
arguments:
- a pointer to a png_struct
- a pointer to a structure where input data can be stored
- 32-bit unsigned int to indicate number of bytes to read
The input function should invoke png_error() to handle any fatal
errors and png_warning() to handle non-fatal errors.