Title

Error LNK2001: unresolved external symbol "struct _iobuf * __cdecl lm_flex_stdin(void)" (?lm_flex_stdin@@YAPEAU_iobuf@@XZ)

Introduction

You might observe this error while building the FNP toolkit in visual studio.

Solution

1. Make sure all the libraries mentioned in the makefile are linked to the project .
2. It could also be due to the lm_redir_std. in the machind folder . The 'ifdef PC' part might be  making the build happen using the wrong defines. You can change it to a ifndef.

#ifndef MAINWIN_FLEXNET_H_LM_REDIR_STD_H_
#define MAINWIN_FLEXNET_H_LM_REDIR_STD_H_

#include <stdio.h>

#ifndef PC
FILE* lm_flex_stdout();
FILE* lm_flex_stderr();
FILE* lm_flex_stdin();
#else
#define lm_flex_stdout() stdout
#define lm_flex_stderr() stderr
#define lm_flex_stdin() stdin
#endif

Outcome

The Build will be successful post taking care of the above 2 points.