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Comments in headers are changed a bit: removed adoc-specific stuff,
markdown is used instead

PUBLISHED_FROM=9242cce85cc52a47a197d377e7e23804721a6bb5

docs/c-api/http.h/mg_url_decode.md

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+---
+title: "mg_url_decode()"
+decl_name: "mg_url_decode"
+symbol_kind: "func"
+signature: |
+  int mg_url_decode(const char *src, int src_len, char *dst, int dst_len,
+                    int is_form_url_encoded);
+---
+
+Decode URL-encoded string.
+
+Source string is specified by (`src`, `src_len`), and destination is
+(`dst`, `dst_len`). If `is_form_url_encoded` is non-zero, then
+`+` character is decoded as a blank space character. This function
+guarantees to `\0`-terminate the destination. If destination is too small,
+then source string is partially decoded and `-1` is returned. Otherwise,
+a length of decoded string is returned, not counting final `\0`. 
+