ввод строки с разделителями (delimited string input)
Имя (Name)
getline, getdelim - delimited string input
Синопсис (Synopsis)
#include <stdio.h>
ssize_t getline(char **restrict
lineptr, size_t *restrict
n,
FILE *restrict
stream);
ssize_t getdelim(char **restrict
lineptr, size_t *restrict
n,
int
delim, FILE *restrict
stream);
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
Описание (Description)
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.
Возвращаемое значение (Return value)
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.
Ошибки (Error)
EINVAL
Bad arguments (n or lineptr is NULL, or stream is not
valid).
ENOMEM
Allocation or reallocation of the line buffer failed.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│Interface
│ Attribute
│ Value
│
├──────────────────────────────────────┼───────────────┼─────────┤
│getline
(), getdelim
() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
Стандарты (Conforming to)
Both getline
() and getdelim
() were originally GNU extensions.
They were standardized in POSIX.1-2008.
Примеры (Examples)
#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);
}
Смотри также (See also)
read(2), fgets(3), fopen(3), fread(3), scanf(3)