curl/docs/libcurl/curl_easy_unescape.md
Daniel Stenberg eefcc1bda4
docs: introduce "curldown" for libcurl man page format
curldown is this new file format for libcurl man pages. It is markdown
inspired with differences:

- Each file has a set of leading headers with meta-data
- Supports a small subset of markdown
- Uses .md file extensions for editors/IDE/GitHub to treat them nicely
- Generates man pages very similar to the previous ones
- Generates man pages that still convert nicely to HTML on the website
- Detects and highlights mentions of curl symbols automatically (when
  their man page section is specified)

tools:

- cd2nroff: converts from curldown to nroff man page
- nroff2cd: convert an (old) nroff man page to curldown
- cdall: convert many nroff pages to curldown versions
- cd2cd: verifies and updates a curldown to latest curldown

This setup generates .3 versions of all the curldown versions at build time.

CI:

Since the documentation is now technically markdown in the eyes of many
things, the CI runs many more tests and checks on this documentation,
including proselint, link checkers and tests that make sure we capitalize the
first letter after a period...

Closes #12730
2024-01-23 00:29:02 +01:00

74 lines
1.9 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
SPDX-License-Identifier: curl
Title: curl_easy_unescape
Section: 3
Source: libcurl
See-also:
- curl_easy_escape (3)
- curl_free (3)
---
# NAME
curl_easy_unescape - URL decodes the given string
# SYNOPSIS
~~~c
#include <curl/curl.h>
char *curl_easy_unescape(CURL *curl, const char *input,
int inlength, int *outlength);
~~~
# DESCRIPTION
This function converts the URL encoded string **input** to a "plain string"
and returns that in an allocated memory area. All input characters that are URL
encoded (%XX where XX is a two-digit hexadecimal number) are converted to their
binary versions.
If the **length** argument is set to 0 (zero), curl_easy_unescape(3)
uses strlen() on **input** to find out the size.
If **outlength** is non-NULL, the function writes the length of the returned
string in the integer it points to. This allows proper handling even for
strings containing %00. Since this is a pointer to an *int* type, it can
only return a value up to *INT_MAX* so no longer string can be returned in
this parameter.
Since 7.82.0, the **curl** parameter is ignored. Prior to that there was
per-handle character conversion support for some old operating systems such as
TPF, but it was otherwise ignored.
You must curl_free(3) the returned string when you are done with it.
# EXAMPLE
~~~c
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
int decodelen;
char *decoded = curl_easy_unescape(curl, "%63%75%72%6c", 12, &decodelen);
if(decoded) {
/* do not assume printf() works on the decoded data! */
printf("Decoded: ");
/* ... */
curl_free(decoded);
}
curl_easy_cleanup(curl);
}
}
~~~
# AVAILABILITY
Added in 7.15.4 and replaces the old curl_unescape(3) function.
# RETURN VALUE
A pointer to a null-terminated string or NULL if it failed.