Azure Table Service REST API: JSON format is not supported -

i'm trying request line azure table storage using rest api , c++, got following error:

<?xml version="1.0" encoding="utf-8" standalone="yes"?> <error xmlns="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">   <cod_e>jsonformatnotsupported</cod_e>   <message xml:lang="en-us">json format not supported. requestid:0ccb3b9b-0002-0029-3389-0d2fa1000000 time:2016-09-13t06:39:13.3155742z</message> </error> 

here request:

get https://<myaccount>.table.core.windows.net/<mytable>(partitionkey='<mypartition>',rowkey='<myrow>')?<sharedsignature> 

here how fill request headers, https://msdn.microsoft.com/en-us/library/dd179428.aspx:

std::string sharedaccesssignature("<sharedsignature>"); std::string datetime(getdatetime()); std::string stringtosign(datetime + "\n/" + account + "/" + "<mytable>"); std::string request("(partitionkey='<mypartition>',rowkey='<myrow>')"); stringtosign += request; std::string signaturestring(hmacsha256(stringtosign, sharedaccesssignature));  headers["authorization"] = "sharedkeylite " + account + ":" + signaturestring; headers["dataserviceversion"] = "3.0;netfx"; headers["maxdataserviceversion"] = "3.0;netfx"; headers["x-ms-version"] = "2015-12-11"; headers["x-ms-date"] = datetime; headers["accept"] = "application/json;odata=verbose"; headers["accept-charset"] = "utf-8"; 

the table exists , not empty.
please advise what's wrong?

update 1
removing sharedsignature request, i.e. get https://<myaccount>.table.core.windows.net/<mytable>(partitionkey='<mypartition>',rowkey='<myrow>') leads same result.
removing authorization header request leads same result too.

update 2
putting https://<myaccount>.table.core.windows.net/<mytable>(partitionkey='<mypartition>',rowkey='<myrow>')?<sharedsignature> in browser produces valid response, in atom format.

<?xml version="1.0" encoding="utf-8"?> <entry    xml:base="https://<myaccount>.table.core.windows.net/"    xmlns="http://www.w3.org/2005/atom"    xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices"    xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"    m:etag="w/&quot;datetime'2016-09-13t05%3a29%3a51.211538z'&quot;">   <id>https://<myaccount>.table.core.windows.net/<mytable> (partitionkey='<mypartition>',rowkey='<myrow>')</id>   <category term="<myaccount>.<mytable>" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" />   <link rel="edit" title="<mytable>" href="<mytable> (partitionkey='<mypartition>',rowkey='<myrow>')" />   <title />   <updated>2016-09-13t11:25:19z</updated>   <author><name /></author>   <content type="application/xml">     <m:properties>       <d:partitionkey><mypartition></d:partitionkey>       <d:rowkey><myrow></d:rowkey>       <d:timestamp m:type="edm.datetime">2016-09-13t05:29:51.211538z</d:timestamp>       <d:score m:type="edm.int32">1050</d:score>     </m:properties>   </content> </entry> 

update 3
investigation situation using curl found adding accept: application/json;odata=fullmetadata request headers leads error above. default accept */* in headers produces valid atom response.

finally, got it!
issue in shared signature.
while looking @ found sv=2012-02-12 part, , assumed, means api version. version, before json support introduced! created new shared signature , got json following curl command.
curl -v -h "accept: application/json;odata=nometadata" -h "x-ms-version: 2015-12-11" "https://<myaccount>.table.core.windows.net/<mytable>(partitionkey='<mypartition>',rowkey='<myrow>')?<mysharedsignature>"

so, everyone, face same issue in future: please check signature first!