getline, getdelim - delimited string input

       For an explanation of the terms used in this section, see attributes(7).
       ┌─────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                                                                   │ Attribute     │ Value   │
       ├─────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │ getline(), getdelim()                                                       │ Thread safety │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

getline()  reads  an  entire line from stream, storing the address of the buffer containing the text into
       *lineptr.  The buffer is null-terminated and includes the newline character, if one was found.

       If *lineptr is set to NULL before the call, then getline() will allocate a buffer for storing  the  line.
       This buffer should be freed by the user program even if getline() failed.

       Alternatively,  before  calling getline(), *lineptr can contain a pointer to a malloc(3)-allocated buffer
       *n bytes in size.  If the buffer is not large  enough  to  hold  the  line,  getline()  resizes  it  with
       realloc(3), updating *lineptr and *n as necessary.

       In  either  case, on a successful call, *lineptr and *n will be updated to reflect the buffer address and
       allocated size respectively.

       getdelim() works like getline(), except that a line delimiter other than newline can be specified as  the
       delimiter  argument.  As with getline(), a delimiter character is not added if one was not present in the
       input before end of file was reached.

EINVAL Bad arguments (n or lineptr is NULL, or stream is not valid).

       ENOMEM Allocation or reallocation of the line buffer failed.

       #define _GNU_SOURCE
       #include <stdio.h>
       #include <stdlib.h>

       int
       main(int argc, char *argv[])
       {
           FILE *stream;
           char *line = NULL;
           size_t len = 0;
           ssize_t nread;

           if (argc != 2) {
               fprintf(stderr, "Usage: %s <file>\n", argv[0]);
               exit(EXIT_FAILURE);
           }

           stream = fopen(argv[1], "r");
           if (stream == NULL) {
               perror("fopen");
               exit(EXIT_FAILURE);
           }

           while ((nread = getline(&line, &len, stream)) != -1) {
               printf("Retrieved line of length %zd:\n", nread);
               fwrite(line, nread, 1, stdout);
           }

           free(line);
           fclose(stream);
           exit(EXIT_SUCCESS);
       }

       GNU, POSIX.1-2008.

       Standard C library (libc, -lc)

       getline, getdelim - delimited string input

       On success, getline() and getdelim() return the  number  of  characters  read,  including  the  delimiter
       character, but not including the terminating null byte ('\0').  This value can be used to handle embedded
       null bytes in the line read.

       Both  functions return -1 on failure to read a line (including end-of-file condition).  In the event of a
       failure, errno is set to indicate the error.

       If *lineptr was set to NULL before the call, then the buffer should be freed by the user program even  on
       failure.

read(2), fgets(3), fopen(3), fread(3), scanf(3)

Linux man-pages 6.9.1                              2024-06-15                                         getline(3)

       POSIX.1-2008.

#include<stdio.h>ssize_tgetline(char**restrictlineptr,size_t*restrictn,FILE*restrictstream);ssize_tgetdelim(char**restrictlineptr,size_t*restrictn,intdelim,FILE*restrictstream);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getline(), getdelim():
           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:
               _GNU_SOURCE