Yoctopuce Yocto-Display, Руководство пользователя

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http://127.0.0.1:4444/bySerial/YD128X32-12345/dataLogger.json?id=display &utc=1389801080
21.3. Using dynamic libraries
The low level Yoctopuce API is available under several formats of dynamic libraries written in C. The
sources are available with the C++ API. If you use one of these low level libraries, you do not need
the
VirtualHub anymore.
Filename Platform
libyapi.dylib Max OS X
libyapi-amd64.so Linux Intel (64 bits)
libyapi-armel.so Linux ARM EL
libyapi-armhf.so Linux ARM HL
libyapi-i386.so Linux Intel (32 bits)
yapi64.dll Windows (64 bits)
yapi.dll Windows (32 bits)
These dynamic libraries contain all the functions necessary to completely rebuild the whole high level
API in any language able to integrate these libraries. This chapter nevertheless restrains itself to
describing basic use of the modules.
Driving a module
The three essential functions of the low level API are the following:
int yapiInitAPI ( int connection_type, char * errmsg );
int yapiUpdateDeviceList ( int forceupdate, char * errmsg );
int yapiHTTPRequest ( char * device, char * request, char * buffer, int buffsize, int * fullsize,
char * errmsg );
The yapiInitAPI function initializes the API and must be called once at the beginning of the program.
For a USB type connection, the connection_type parameter takes value 1. The errmsg parameter
must point to a 255 character buffer to retrieve a potential error message. This pointer can also point
to
null . The function returns a negative integer in case of error, zero otherwise.
The yapiUpdateDeviceList manages the inventory of connected Yoctopuce modules. It must be
called at least once. To manage hot plug and detect potential newly connected modules, this function
must be called at regular intervals. The
forceupdate parameter must take value 1 to force a hardware
scan. The errmsg parameter must point to a 255 character buffer to retrieve a potential error
message. This pointer can also point to null . The function returns a negative integer in case of error,
zero otherwise.
Finally, the yapiHTTPRequest function sends HTTP requests to the module REST API. The device
parameter contains the serial number or the logical name of the module which you want to reach.
The
request parameter contains the full HTTP request (including terminal line breaks). buffer points
to a character buffer long enough to contain the answer. buffsize is the size of the buffer. fullsize is a
pointer to an integer to which will be assigned the actual size of the answer. The errmsg parameter
must point to a 255 character buffer to retrieve a potential error message. This pointer can also point
to
null . The function returns a negative integer in case of error, zero otherwise.
The format of the requests is the same as the one described in the VirtualHub et HTTP GET section.
All the character strings used by the API are strings made of 8-bit characters: Unicode and UTF8 are
not supported.
The resutlt returned in the buffer variable respects the HTTP protocol. It therefore includes an HTTP
header. This header ends with two empty lines, that is a sequence of four ASCII characters 13, 10,
13, 10.
Here is a sample program written in pascal using the yapi.dll DLL to read and then update the
luminosity of a module.
21. Using with unsupported languages
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