Read a character from a stream
Synopsis:
#include <stdio.h>
int fgetc( FILE* fp );
Arguments:
- fp
- The stream from which you want to read a character.
Library:
libc
Use the -l c option to
qcc
to link against this library.
This library is usually included automatically.
Description:
The fgetc() function reads the next character from the stream
specified by fp.
Returns:
- If successful, fgetc() returns the next character from fp,
cast as (int)(unsigned char).
- If the end-of-file indicator for the stream is set or the end of the file has been reached,
fgetc() sets the end-of-file indicator and returns EOF.
- If an error occurred, fgetc() sets the error indicator for the stream, sets
errno,
and returns EOF.
Note:
Use
feof()
or
ferror()
to distinguish an end-of-file condition from an error.
Errors:
- EAGAIN
- The O_NONBLOCK flag is set for the file descriptor
underlying fp, and the process would be delayed in the
write operation.
- EBADF
- The file descriptor underlying fp isn't a valid
file descriptor that's open for reading.
- EINTR
- The read operation was terminated due to the receipt of a signal,
and no data was transferred.
- EIO
- One of the following:
- A physical I/O error occurred.
- The process is in a background process group attempting to read from
its controlling terminal, and either the process is ignoring or
blocking the SIGTTIN signal or the process group is
orphaned.
- (QNX Neutrino extension) The filesystem resides on a removable media
device, and the media has been forcibly removed.
- ENOMEM
- Insufficient space is available.
- ENXIO
- A request was made of a nonexistent device, or the request was outside
the capabilities of the device.
- EOVERFLOW
- The file is a regular file, and an attempt was made to read at or
beyond the offset maximum associated with the corresponding stream.
Examples:
#include <stdio.h>
#include <stdlib.h>
int main( void )
{
FILE *fp;
int c;
fp = fopen( "file", "r" );
if( fp != NULL ) {
while( (c = fgetc( fp )) != EOF ) {
fputc( c, stdout );
}
fclose( fp );
return EXIT_SUCCESS;
}
return EXIT_FAILURE;
}
Classification:
ANSI,
POSIX 1003.1
Safety: |
|
Cancellation point |
Yes |
Interrupt handler |
No |
Signal handler |
No |
Thread |
Yes |