[c++] 'uint32_t' does not name a type

I'm trying to compile a C++ software package that was written in 2007 and I'm getting this error:

error: ‘uint32_t’ does not name a type

This is happening in 64-bit Ubuntu using g++ 4.5.2. It compiles fine on 64-bit CentOS using g++ 4.1.2.

Is there an #include or a compiler flag that I'm missing? Or, should I use typedef to assign uint32_t to a size_t or maybe an unsigned int?

I had tha same problem trying to compile a lib I download from the internet. In my case, there was already a #include <cstdint> in the code. I solved it adding a:

using std::uint32_t;

if it happened when you include opencv header.

I would recommand that change the order of headers.

put the opencv headers just below the standard C++ header.

like this:

#include<iostream>
#include<opencv2/core/core.hpp>
#include<opencv2/highgui/highgui.hpp>

You need to include iostream

#include <iostream>
using namespace std;

The other answers assume that your compiler is C++11 compliant. That is fine if it is. But what if you are using an older compiler?

I picked up the following hack somewhere on the net. It works well enough for me:

  #if defined __UINT32_MAX__ or UINT32_MAX
  #include <inttypes.h>
  #else
  typedef unsigned char uint8_t;
  typedef unsigned short uint16_t;
  typedef unsigned long uint32_t;
  typedef unsigned long long uint64_t;
  #endif

It is not portable, of course. But it might work for your compiler.

You need to #include <cstdint>, but that may not always work.

The problem is that some compiler often automatically export names defined in various headers or provided types before such standards were in place.

Now, I said "may not always work." That's because the cstdint header is part of the C++11 standard and is not always available on current C++ compilers (but often is). The stdint.h header is the C equivalent and is part of C99.

For best portability, I'd recommend using Boost's boost/cstdint.hpp header, if you're willing to use boost. Otherwise, you'll probably be able to get away with #include'ing <cstdint>.

Add the following in the base.mk file. The following 3rd line is important -include $(TOP)/defs.mk

CFLAGS=$(DEBUG) -Wall -W -Wwrite-strings 
CFLAGS_C=-Wmissing-prototypes
CFLAGS_CXX=-std=c++0x
LDFLAGS=
LIBS=

to avoid the #error This file requires compiler and library support for the upcoming ISO C++ standard, C++0x. This support is currently experimental, and must be enabled with the -std=c++0x or -std=gnu++0x compiler options

just navigate to /usr/include/x86_64-linux-gnu/bits open stdint-uintn.h and add these lines

typedef __uint8_t uint8_t;
typedef __uint16_t uint16_t;
typedef __uint32_t uint32_t;
typedef __uint64_t uint64_t;

again open stdint-intn.h and add

typedef __int8_t int8_t;
typedef __int16_t int16_t;
typedef __int32_t int32_t;
typedef __int64_t int64_t;

note these lines are already present just copy and add the missing lines cheerss..

I also encountered the same problem on Mac OSX 10.6.8 and unfortunately adding #include <stdint.h> or <cstdint.h> to the corresponding file did not solve my problem. However, after more search, I found this solution advicing to add #include <sys/types.h> which worked well for me!