Is it error?

[MarlikAlmighty]

/home/user/projects/dev/mongoose/mongoose.c:764:15: error: conflicting types for ‘mg_file_read’; have ‘struct mg_str(struct mg_fs *, const char *)’
  764 | struct mg_str mg_file_read(struct mg_fs *fs, const char *path) {
      |               ^~~~~~~~~~~~
In file included from /home/user/projects/dev/mongoose/mongoose.c:20:
/home/user/projects/dev/mongoose/mongoose.h:1085:8: note: previous declaration of ‘mg_file_read’ with type ‘char *(struct mg_fs *, const char *)’
 1085 | char * mg_file_read(struct mg_fs *fs, const char *path);

[scaprile]

It is hard for me to tell you what you are doing wrong, particularly when you don't say what you are doing.
Please be kind and ask a proper, specific question, regarding Mongoose, not basic how to build C code issues, please.
Mongoose is CI/CD tested on several platforms every day.

[scaprile]

What exactly are you building, with which, on where.

[MarlikAlmighty]

Hello, sorry.

char * mg_file_read(struct mg_fs *fs, const char *path); // in mongoose.h
struct mg_str mg_file_read(struct mg_fs *fs, const char *path) // in mongoose.c

[scaprile]

What is that ?

mongoose/mongoose.h

Line 1085 in 8fafcf6

struct mg_str mg_file_read(struct mg_fs *fs, const char *path);

mongoose/mongoose.c

Line 764 in 8fafcf6

struct mg_str mg_file_read(struct mg_fs *fs, const char *path) {

Whatever you are mixing, it is your problem

[MarlikAlmighty]

Sorry, I don't understand why I have different return values. I'll try to refill it.

[scaprile]

Please see our documentation, and follow the guidelines in our tutorials.

https://mongoose.ws/documentation/#2-minute-integration-guide