|FGETC(3P)||POSIX Programmer's Manual||FGETC(3P)|
int fgetc(FILE *stream);
If the end-of-file indicator for the input stream pointed to by stream is not set and a next byte is present, the fgetc() function shall obtain the next byte as an unsigned char converted to an int, from the input stream pointed to by stream, and advance the associated file position indicator for the stream (if defined). Since fgetc() operates on bytes, reading a character consisting of multiple bytes (or ``a multi-byte character'') may require multiple calls to fgetc().
The fgetc() function may mark the last data access timestamp of the file associated with stream for update. The last data access timestamp shall be marked for update by the first successful execution of fgetc(), fgets(), fread(), fscanf(), getc(), getchar(), getdelim(), getline(), gets(), or scanf() using stream that returns data not supplied by a prior call to ungetc().
- The O_NONBLOCK flag is set for the file descriptor underlying stream and the thread would be delayed in the fgetc() operation.
- The file descriptor underlying stream is not a valid file descriptor open for reading.
- The read operation was terminated due to the receipt of a signal, and no data was transferred.
- A physical I/O error has occurred, or the process is in a background process group attempting to read from its controlling terminal, and either the calling thread is blocking SIGTTIN or the process is ignoring SIGTTIN or the process group of the process is orphaned. This error may also be generated for implementation-defined reasons.
- The file is a regular file and an attempt was made to read at or beyond the offset maximum associated with the corresponding stream.
The fgetc() function may fail if:
- Insufficient storage space is available.
- A request was made of a nonexistent device, or the request was outside the capabilities of the device.
The following sections are informative.
The ferror() or feof() functions must be used to distinguish between an error condition and an end-of-file condition.
The Base Definitions volume of POSIX.1‐2017, <stdio.h>
Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .
|2017||IEEE/The Open Group|