Euresys::EGenTL

Euresys::EGenTL is a library of C++ classes that provide the same functionality as standard GenICam GenTL, but with a more user-friendly interface. For example, it uses std::string instead of raw char pointers, and error codes are transformed into exceptions. Euresys::EGenTL also takes care of locating the GenTL producer and loading the functions it exports.

This library is implemented entirely in C++ header files. As a result, you can simply include the relevant header file:

 #include <EGenTL.h>

Instead of the raw, low-level C functions that GenTL defines, we get a Euresys::EGenTL object that represents the GenTL producer:

Each GenTL function is available as a member method of Euresys::EGenTL. GenTL function names start with an upper-case prefix. In Euresys::EGenTL, method names start with the same prefix, but written in lower-case. For example, the GCReadPort function is exposed as the gcReadPort method, and the TLOpenInterface function as the tlOpenInterface method.
All GenTL functions return a GC_ERROR code indicating success or failure. When a function returns a code other than GC_ERR_SUCCESS, an exception is thrown. This removes the burden of manually checking error codes after each function call.
Since GenTL functions return a GC_ERROR, output values are returned through pointers passed as arguments. Euresys::EGenTL methods offer a more natural interface; they return the output value directly:
```
GC_API TLGetNumInterfaces(TL_HANDLE hTL, uint32_t *piNumIfaces);
```
```
uint32_t tlGetNumInterfaces(TL_HANDLE tlh);
```
(Note that GC_API is defined as GC_IMPORT_EXPORT GC_ERROR GC_CALLTYPE. It is simply a GC_ERROR decorated with calling convention and DLL import/export attributes.)

For GenTL functions that deal with text, the corresponding Euresys::EGenTL methods convert from char * to std::string and vice-versa:

GC_API TLGetInterfaceID(TL_HANDLE hTL, uint32_t iIndex,
                        char *sID, size_t *piSize);

std::string tlGetInterfaceID(TL_HANDLE tlh, uint32_t index);

Some GenTL functions retrieve information about the camera or frame grabber. These functions fill a void * buffer with a value, and indicate in an INFO_DATATYPE the actual type of the value. Euresys::EGenTL uses C++ templates to make these functions easy to use:
```
GC_API GCGetInfo(TL_INFO_CMD iInfoCmd, INFO_DATATYPE *piType,
                 void *pBuffer, size_t *piSize);
```
```
template<typename T> T gcGetInfo(TL_INFO_CMD cmd);
```