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UNGETC(3)             DragonFly Library Functions Manual             UNGETC(3)


ungetc -- un-get character from input stream


Standard C Library (libc, -lc)


#include <stdio.h> int ungetc(int c, FILE *stream);


The ungetc() function pushes the character c (converted to an unsigned char) back onto the input stream pointed to by stream. The pushed-back characters will be returned by subsequent reads on the stream (in reverse order). A successful intervening call, using the same stream, to one of the file positioning functions (fseek(3), fsetpos(3), or rewind(3)) will discard the pushed back characters. One character of push-back is guaranteed, but as long as there is suffi- cient memory, an effectively infinite amount of pushback is allowed. If a character is successfully pushed-back, the end-of-file indicator for the stream is cleared. The file-position indicator is decremented by each successful call to ungetc(); if its value was 0 before a call, its value is unspecified after the call.


The ungetc() function returns the character pushed-back after the conver- sion, or EOF if the operation fails. If the value of the argument c character equals EOF, the operation will fail and the stream will remain unchanged.


fseek(3), getc(3), setvbuf(3), ungetwc(3)


The ungetc() function conforms to ISO/IEC 9899:1990 (``ISO C90''). DragonFly 3.5 June 4, 1993 DragonFly 3.5

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