Question

Incompatible types in return ?

file.h

struct typeCSVFile {
    NSString *nssPath;
    NSString *nssData;

    NSString ***p_nssData;//
    int iRows;
    int iCols;
};

....

struct typeCSVFile structCSVFile;

....

-(struct structCSVFile) fileCSVRead;

file.m

-(struct structCSVFile) fileCSVRead{

    ...

    return structCSVFile; // <-- Incompatible types in return
}

Answer 1

Possibly, you mean:

 -(struct typeCSVFile) fileCSVRead;

and:

-(struct typeCSVFile) fileCSVRead{
    ...
    return structCSVFile;
}

The type name is struct typeCSVFile, while structCSVFile is an instance of that type. You could also think of using typedef to get rid of the struct part:

typedef struct typeCSVFile typeCSVFile;