---
name: "strsep"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/strsep"
---

# strsep(3)

separate strings

## NAME

**strsep** – separate strings

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<string.h\>**

*char* *\**\

**strsep**(*char \*\*stringp*, *const char \*delim*);

## DESCRIPTION

The **strsep**() function locates, in the string referenced by *\*stringp*, the first occurrence of any character in the string *delim* (or the terminating ‘\\0’ character) and replaces it with a ‘\\0’. The location of the next character after the delimiter character (or NULL, if the end of the string was reached) is stored in *\*stringp*. The original value of *\*stringp* is returned.

An “empty” field (i.e., a character in the string *delim* occurs as the first character of *\*stringp*) can be detected by comparing the location referenced by the returned pointer to ‘\\0’.

If *\*stringp* is initially NULL, **strsep**() returns NULL.

## EXAMPLES

The following uses **strsep**() to parse a string, and prints each token in separate line:

```
char *token, *string, *tofree;
tofree = string = strdup("abc,def,ghi");
if (string == NULL)
	err(1, "strdup");
while ((token = strsep(&string, ",")) != NULL)
	printf("%s\n", token);
free(tofree);
```

The following uses **strsep**() to parse a string, containing tokens delimited by white space, into an argument vector:

```
char **ap, *argv[10], *inputstring;
for (ap = argv; (*ap = strsep(&inputstring, " \t")) != NULL;)
	if (**ap != '\0')
		if (++ap >= &argv[10])
			break;
```

## SEE ALSO

[memchr(3)](/memchr/3.md), [strchr(3)](/strchr/3.md), [strcspn(3)](/strcspn/3.md), [strpbrk(3)](/strpbrk/3.md), [strrchr(3)](/strrchr/3.md), [strspn(3)](/strspn/3.md), [strstr(3)](/strstr/3.md), [strtok(3)](/strtok/3.md)

## HISTORY

The **strsep**() function is intended as a replacement for the **strtok**() function. While the **strtok**() function should be preferred for portability reasons (it conforms to ISO/IEC 9899:1990 (“ISO C90”)) it is unable to handle empty fields, i.e., detect fields delimited by two adjacent delimiter characters, or to be used for more than a single string at a time. The **strsep**() function first appeared in 4.4BSD.