getc(3S)                                                           getc(3S)

NAME
     getc, getchar, fgetc, getw - get character or word from a stream

SYNOPSIS
     #include <stdio.h>

     int getc(FILE *stream);

     int getchar(void);

     int fgetc(FILE *stream);

     int getw(FILE *stream);

DESCRIPTION
     getc() returns the next character (i.e., byte) from the named input
     stream as an unsigned char converted to an int. It also moves the file
     pointer, if defined, ahead one character in stream. getchar() is
     defined as getc(stdin). getc() and getchar() are macros.

     fgetc() behaves like getc(), but is a function rather than a macro.
     fgetc() runs more slowly than getc(), but it takes less space per
     invocation and its name can be passed as an argument to a function.

     getw() returns the next word (i.e., integer) from the named input
     stream. getw() increments the associated file pointer, if defined, to
     point to the next word. The size of a word is the size of an int type
     number, and varies from machine to machine. getw() assumes no special
     alignment in the file.

ERRORS
     The following error code descriptions are function-specific. You will
     find a general description in introprm2(2) or in errno(5).

     The functions fail if:

     EAGAIN      The ONONBLOCK flag is set for the file descriptor under-
                 lying stream, and the process is delayed.

     EBADF       The file descriptor underlying stream is not a valid file
                 descriptor opened for reading.

     EINTR       The read operation was terminated due to the receipt of a
                 signal; no data was transferred.

     EIO         A physical I/O error has occurred, or the process is in a
                 background process group attempting to read from its con-
                 trolling terminal, and either the process is ignoring or
                 blocking the SIGTTIN signal or the process group is
                 orphaned. This error may also be generated for implementa-
                 tion-dependent reasons.




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getc(3S)                                                           getc(3S)

     EOVERFLOW   The file is a regular file and an attempt was made to read
                 at or beyond the offset maximum associated with the corre-
                 sponding stream.

     The fgetc() function may fail if:

     ENOMEM      Insufficient storage space is available.

     ENXIO       A request was made of a non-existent device, or the
                 request was outside the capabilities of the device.

RESULT
     These functions return the constant EOF at end-of-file or upon an
     error and set the EOF or error indicator of stream, respectively.
     Because EOF is a valid integer, ferror() or feof() should be used to
     detect errors.

NOTES
     If the integer value returned by getc(), getchar(), or fgetc() is
     stored into a char type variable and then compared against the integer
     constant EOF, the comparison may never succeed, because sign-extension
     in transferring from char to int is implementation dependent.

     The macro version of getc() evaluates a stream argument more than once
     and may treat side effects incorrectly. In particular, getc(*f++) does
     not work sensibly. Use fgetc() instead.

     Because of possible differences in word length and byte ordering,
     files written using putw() are implementation dependent, and may not
     be read using getw() on a different processor.

     Functions exist for all the above-defined macros. To get the function
     form, the macro name must be undefined (e.g., #undef getc()).

SEE ALSO
     fclose(3S), ferror(3S), fopen(3S), fread(3S), gets(3S), putc(3S),
     scanf(3S), stdio(3S), ungetc(3S), lfs(5), stdio(5).

















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