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GETS(3)               DragonFly Library Functions Manual               GETS(3)


gets - get a line from a stream


Standard C Library (libc, -lc)


#include <stdio.h> char * gets(char *str);


This interface is made obsolete by fgets(3) and gets_s(3). See SECURITY CONSIDERATIONS below. The gets() function is equivalent to fgets(3) with an infinite size and a stream of stdin, except that the newline character (if any) is not stored in the string. It is the caller's responsibility to ensure that the input line, if any, is sufficiently short to fit in the string.


Upon successful completion, gets() returns a pointer to the string. If end-of-file occurs before any characters are read, they return NULL and the buffer contents remain unchanged. If an error occurs, they return NULL and the buffer contents are indeterminate. The gets() function does not distinguish between end-of-file and error, and callers must use feof(3) and ferror(3) to determine which occurred.


[EBADF] The given stream is not a readable stream. The gets() function may also fail and set errno for any of the errors specified for the routine getchar(3).


The gets() function cannot be used securely. Because of its lack of bounds checking, and the inability for the calling program to reliably determine the length of the next incoming line, the use of this function enables malicious users to arbitrarily change a running program's functionality through a buffer overflow attack. It is strongly suggested that the fgets() and gets_s() functions be used in all cases.


fgets(3), gets_s(3)


The gets() function conforms to ISO/IEC 9899:1999 ("ISO C99"). DragonFly 5.7-DEVELOPMENT September 9, 2019 DragonFly 5.7-DEVELOPMENT gets(n) Tcl Built-In Commands gets(n) ______________________________________________________________________________


gets - Read a line from a channel


gets channelId ?varName? ______________________________________________________________________________


This command reads the next line from channelId, returns everything in the line up to (but not including) the end-of-line character(s), and discards the end-of-line character(s). ChannelId must be an identifier for an open channel such as the Tcl standard input channel (stdin), the return value from an invocation of open or socket, or the result of a channel creation command provided by a Tcl extension. The channel must have been opened for input. If varName is omitted the line is returned as the result of the command. If varName is specified then the line is placed in the variable by that name and the return value is a count of the number of characters returned. If end of file occurs while scanning for an end of line, the command returns whatever input is available up to the end of file. If channelId is in non-blocking mode and there is not a full line of input available, the command returns an empty string and does not consume any input. If varName is specified and an empty string is returned in varName because of end-of-file or because of insufficient data in non- blocking mode, then the return count is -1. Note that if varName is not specified then the end-of-file and no-full-line-available cases can produce the same results as if there were an input line consisting only of the end-of-line character(s). The eof and fblocked commands can be used to distinguish these three cases.


This example reads a file one line at a time and prints it out with the current line number attached to the start of each line. set chan [open "some.file.txt"] set lineNumber 0 while {[gets $chan line] >= 0} { puts "[incr lineNumber]: $line" } close $chan


file(n), eof(n), fblocked(n), Tcl_StandardChannels(3)


blocking, channel, end of file, end of line, line, non-blocking, read Tcl 7.5 gets(n)

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